Kinetics study of Si release from silica synthesized from sugarcane waste ash

Abstract

Sugarcane bottom ash (SWA) is a byproduct generated in substantial quantities globally, creating significant environmental challenges due to inadequate disposal practices. This study focused on the extraction of high-purity silica from SWA using the sol-gel method, a process known for its efficiency in producing high-quality materials. Advanced characterization techniques, including X-ray fluorescence (XRF) and X-ray diffraction (XRD), confirmed the successful production of amorphous silica with a purity of 98%, demonstrating the effectiveness of this method. To further evaluate the Si content, the synthesized product underwent chemical treatment using a combination of citric acid, hydrochloric acid, and a salt mixture for a period of 48 h. This critical step improved the properties of the material and prepared it for further analysis. Kinetic parameters were determined to characterize the silicon release behavior under various conditions, providing valuable information on the potential of the material as a slow-release fertilizer. Four mathematical models—first-order equation, power function, parabolic diffusion, and Elovich model—were employed to describe the kinetics of Si release, providing insights into the product’s agricultural applications. The findings suggest that silica synthesized from SWA is not only a sustainable alternative to conventional fertilizers but also supports circular economy principles by transforming waste into valuable resources. Furthermore, this innovation aligns with the Sustainable Development Goals (SDGs) related to responsible consumption, production, and sustainable agriculture. By addressing environmental and agricultural challenges, this research highlights the dual benefits of waste management and resource efficiency. It demonstrates the role of innovative waste valorization strategies in promoting sustainability across industries and unlocking broader applications in the environmental and agricultural sectors, ultimately demonstrating the potential of SWA as a key resource in sustainable development.